1. Field of the Invention:
This invention relates to a method for determining human prolyl 4-hydroxylase, which is useful for the straightforward diagnosis of hepatic diseases.
More particularly, this invention relates to a method for determining human prolyl 4-hydroxylase by enzyme immunoassay according to the sandwich technique using a specific monoclonal antibody and/or a polyclonal antibody.
2. Description of the Prior Art:
Among methods known hitherto for determining human prolyl 4-hydroxylase (referred to hereinafter simply as hPH) in human blood is included a method wherein 4-L-proline in protocollagen labeled with .sup.3 H is used as a substrate and the resultant H labeled water is captured by vacuum distillation and measured for its radioactivity (Hutton et al., Anal. Biochem., 16, 384-394, 1966). Other known methods involve the use of .sup.14 C-proline labeled protocollagen as a substrate followed by the measurement of radioactivity from the resultant 4-hydroxylated .sup.14 C-proline (Juva et al., Anal. Biochem. 15, 77-83, 1966); or the use of (pro-pro-gyl).sub.5 or (pro-pro-gyl).sub.10 as a substrate followed by the capture and measurement of .sup.14 CO.sub.2 released from 2-oxo(1-.sup.14 C)-glutaric acid (Berg et al., J. Biol. Chem., 248, 1175-1182, 1973). Any of these methods, however, has the disadvantages of requiring complicated, tremendous operations and time-consuming measurements. Furthermore, a simple measurement of hPH activity in blood does not reflect the true hPH level, because most of the hPH is present in blood in an enzymologically inactivated state.
Under the circumstances described above, it was quite impossible to measure the quantity of hPH precisely in a simple manner by way of an enzymatic activity-measuring method. Consequently, there is a great demand for developing a new method for effectively and precisely determining hPH in a simple manner in place of the conventional methods accompanied with various disadvantages, especially in the field of diagnosis of hepatic diseases.